I purchased it used. Worked for three months. I trrned it off for one week while I was gone. Unpluged power. When I tried to use it again it shut down imeadiately. Power supply ok. I unpluge different boards, ram memory and still won't run. One time it ran for about 20 seconds. 3.4 G processor, 4 Gig Ram, Dual digital Monitor card. I have tried another power supply but no results. Any idea what it might be. Acts like it does not recognine the blower is running.